1. Field of the Invention
This invention relates to low oil potato chips which are crisp and flavorful.
2. Description of the Prior Art
Conventional potato chip products are prepared by the basic steps of slicing peeled raw potatoes and frying them in oil at 350.degree. F. for 2 to 4 minutes, or until a moisture content of approximately 1%-2% by weight is achieved, for example, by frying for 3 minutes at 350.degree. F. The fried chips are then salted and packaged.
The moisture content of raw potato slices normally is from 75% to 85%, depending on environmental growing conditions and varieties. When potato slices are fried in oil at high temperature, this substantial amount of moisture present boils explosively. This results in burst cell walls, and consequently, the formation of capillary holes and voids. Oil adheres to the surfaces of the chips and is also absorbed into the holes and voids in the slices, particularly if the chips leave the drying oil, are exposed to the atmosphere, and cool, creating a vacuum effect. For these reasons, regular potato chips have high oil contents, ranging from 35% to 39%, and even as high as 42%.
The oil content of potato chips is important for many reasons. Oil is a costly raw material and is an important determinant of chip cost. From the standpoint of good nutrition, it is desirable to maintain a low level of oil in chips. A high oil content not only is costly to the processor but often renders the chips greasy or oily and hence, less desirable to consumers. On the other hand, it is possible to make chips so low in oil that they lack flavor and seem harsh in texture.
Chip producers generally are interested in making acceptable chips of lower oil contents than the 35%-39% norm. A large segment of the population, particularly those of middle age and older, is generally interested in reducing its intake of both fats and calories. Moreover, the relative and absolute size of this segment of the population is increasing.
Accordingly, in recent years the art has begun to recognize the desirability of reducing the oil content of potato chip products from both nutritional and cost standpoints. However, past attempts at producing low oil content chips have not been commercially successful, since any significant reduction in oil content has come at the expense of the desired organoleptic properties, particularly as to taste and texture.
The state of the art in this field may be ascertained by consideration of the following references.
Lee et al., in U.S. Pat. No. 4,721,625, for example, provides a process of preparing low oil potato chips by partially frying chip slices in hot oil, transferring the partially fried chip slices to an oxygen-free atmosphere, removing substantially all of the residual oil on the slices by blasting with saturated steam, and drying in an atmosphere of superheated steam. However, a substantial investment in capital plant and equipment is required to convert a conventional potato chip manufacturing facility to the Lee process.
Nonaka et al., in U.S. Pat. No. 3,846,572, discloses a process for preparing fried potato products of decreased oil content by freezing the raw potato strips in dichlorodifluoromethane, leaching in water, frying in oil, and thereafter removing excess oil on the surface of the strips by immersing in oil-free dichlorodifluoromethane. However, dichlorodifluoromethane is considered harmful to the ozone layer and, for this reason, is not a readily available chemical product.
Gold, in U.S. Pat. No. 3,424,591, describes a process for preparing French fried potato products having a reduced oil content by treating the potato pieces prior to frying with an aqueous solution of a methyl cellulose. In the Gold process, a thin coating of a thermal gel of methylcellulose and bound water is formed on the potato pieces. It has been determined, however, that thermal gel-coated potato chips contain over 10% by weight water compared to only 4% or less in uncoated potato chips. This high water content causes thermal gel-coated chips to exhibit a soggy texture which is unacceptable to the consumer. Furthermore, thermal gel potato chips achieve an oil reduction of only 4%, which is marginal at best.
Olson et al., in U.S. Pat. No. 4,511,583, describes a process for preparing a battered and breaded food item with reduced oil absorption. The process comprises applying a starch or gelatin film to the batter to prevent oil absorption by the finished breading product upon frying. However, no mention is made of potato chip products containing starch or gelatin films.
Morley, in U.S. Pat. No. 4,565,702, describes coating of insoluble dietary fibers derived from cereal bran with soluble dietary fibers of alignates, gums, pectin, mucillages and plant exudates to mask the taste and texture of the cereal bran. Other soluble dietary fibers are disclosed as useful, including biosynthetic or fermentation products such as dextran, xanthan and curdan; and chemically modified cellulose, pectin and alignate materials. Synthetic products including polyvinylpyrrolidone, carboxyvinyl polymers and polyethylene oxide polymers were mentioned as suitable soluble fibers for the purpose intended. However, there was no suggestion that any soluble dietary fiber could be used for making deep fried potato products, or particularly, for reducing oil absorption into potato chip products.
Accordingly, it is an object of this invention is to provide a low oil potato chip product which is crisp and flavorful.
Another object of the invention is to provide an economical process for making such low oil potato chips.
These and other objects and features of the invention will be made apparent from the following description of the invention.